Silicate Materials, Method For Their Manufacture, And Method For Using Such Silicate Materials For Adsorptive Fluid Separations

ABSTRACT

Embodiments of crystalline, titanium silicate molecular sieves are described having a formula representing mole ratios of oxides of n M 1 O:TiO 2 :y SiO 2 :zH 2 O:wX where Mi refers to a metal cation or mixture of metal cations; n is from about 1 to about 2; y is from about 1 to about 10; z is from 0 to about 100; X is a halide anion other than fluorine, or combination of halide anions that excludes fluorine; and w is greater than 0. The pore size of the sieves can be adjusted by ion exchanging Mi cations with a suitable amount of another species. Embodiments of the invention are useful for various adsorptive fluid separation processes, including pressure swing adsorption processes. For example, disclosed embodiments are useful for separating methane from air.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the earlier filing date ofU.S. provisional application No. 60/817,536, filed on Jun. 28, 2006,which is incorporated herein by reference.

FIELD

The present disclosure concerns a method for making silicate materials,such as titanium silicates, materials made by the method, andembodiments of a method for using such materials for adsorptive fluidseparations.

BACKGROUND

I. Zeolites

Zeolites typically are considered to be crystalline, porousaluminosilicates. In the late 1950s, Milton and coworkers (U.S. Pat.Nos. 2,882,243 and 2,882,244) determined that uniformly porous,internally charged aluminosilicate crystals could be made analogous tomolecular sieve zeolites found in nature. Synthetic aluminosilicatezeolite molecular sieves are now used in numerous, commerciallyimportant catalytic, adsorptive and ion-exchange applications.Aluminosilicate zeolites provide a unique combination of high surfacearea and uniform porosity that is dictated by the “framework” structureof the zeolite crystals coupled with the electrostatically charged sitesinduced by coordinated metal atoms, such as tetrahedrally coordinatedAl⁺³ Many “active” charged sites are readily accessible to molecules ofthe proper size and geometry for adsorptive or catalytic interactions.Further, the charge-compensating cations are electrostatically, notcovalently, bound to the aluminosilicate framework. As a result, suchcations are generally base exchangeable for other cations with differentinherent properties. This provides significant flexibility for modifyingactive sites whereby specific adsorbents aid catalysts can be tailoredfor a particular utility.

While a relatively large number of aluminosilicate materials aretheoretically possible (see, for example, “Zeolite Molecular Sieves,”Chapter 2, 1974, D. W. Breck), to date only a relatively small number(approximately 150) have been identified. While compositional nuanceshave been described in publications, such as U.S. Pat. Nos. 4,524,055,4,603,040 and 4,606,899, totally new aluminosilicate frameworkstructures are rarely discovered. As a result, various approaches havebeen taken to replace aluminum or silicon in zeolite synthesesostensibly to (1) generate either new zeolite-like framework structuresor (2) induce the formation of qualitatively different active sites thanare available in analogous aluminosilicate-based materials. E. M.Flanigan and coworkers have prepared aluminophosphate-based molecularsieves. (J. Am. Chem. Soc., 104, p 1146 (1982); Proceedings of the 7thInternational Zeolite Conference, pp. 103-112, 1986). However, thesite-inducing Al⁺³ is essentially neutralized by the P⁺⁵, imparting azero net charge to the framework. Thus, while a new class of “molecularsieves” was created, they lack “active” charged sites.

Realizing this inherent deficiency, there is a new emphasis onsynthesizing mixed aluminosilicate-metal oxide and mixedaluminophosphate-metal oxide framework systems. This has generatedapproximately 200 new compositions. All of these new compositions suffereither from the active-site-removing effect of incorporated P⁺⁵ or thesite-diluting effect of incorporating an effectively neutral,tetrahedral +4 metal into an aluminosilicate framework. No significantutility has been demonstrated for any of these materials.

The most straightforward method for potentially generating newstructures or qualitatively different sites than those induced byaluminum would be direct substitution of some charge-inducing speciesfor aluminum in a zeolite-like structure. The most notably successfulexample of this approach appears to be substitutions using boron, in thecase of ZSM-5 analogs, or iron. [See, for example, EPA 68,796 (1983),Taramasso et al., Proceedings of the 5th International ZeoliteConference, pp. 40-48 (1980); J. W. Ball et al., Proceedings of the 7thInternational Zeolite Conference, pp. 137-144 (1986); and U.S. Pat. No.4,280,305 to Kouenhowen et al.] The substituting species is incorporatedonly at low amounts, which raises doubt concerning whether the speciesare occluded or framework incorporated.

U.S. Pat. No. 3,329,481 ostensibly describes a method for synthesizingcharge-bearing (exchangeable) titaniumsilicates under conditions similarto aluminosilicate zeolite formation if the titanium was present as a“critical reagent”+III peroxo species. These materials were called“titanium zeolites.” No evidence, other than some questionable X-raydiffraction (XRD) patterns, was presented to support this conclusion.The conclusions stated in the '481 patent generally have been dismissedby the zeolite research community. [See, for example, D. W. Breck,Zeolite Molecular Sieves, p. 322 (1974); R. M. Barrer, HydrothermalChemistry of Zeolites, p. 293 (1982); G. Perego et al., Proceedings of7th International Zeolite Conference, p. 129 (1986).] For all but oneend member of this series of materials (designated TS materials), theXRD patterns presented indicate phases too dense to be molecular sieves.

Naturally occurring titanosilicates also are known. For example, anaturally occurring alkaline titanosilicate, identified as “Zorite,” wasdiscovered in trace quantities on the Siberian Tundra in 1972. See, A.N. Mer'kov et. al, Zapiski Vses Mineralog. Obshch., pp. 54-62 (1973).The published XRD pattern was challenged and a proposed structure waslater reported in an article entitled “The OD Structure of Zorite,”Sandomirskii et al., Sov. Phys. Crystallogr. 24 (6), November-December1979, pp. 686-693.

In 1983, trace levels of tetrahedral Ti(IV) were reported in a ZSM-5analog. M. Taramasso et al.; U.S. Pat. No. 4,410,501 (1983); G. Peregoet al., Proceedings of the 7th International Zeolite Conference, p. 129(1986). More recently, mixed aluminosilicate-titanium(IV) structureshave been reported [EPA 179,876 (1985); EPA 181,884 (1985)] which, alongwith TAPO [EPA 121,232 (1985)], appear to have no possibility of activetitanium sites, and hence likely no utility.

II. U.S. Pat. Nos. 4,853,202, 4,938,939, and 5,989,316

U.S. Pat. No. 4,853,202, entitled “Large-Pored Crystalline TitaniumMolecular Sieve Zeolites,” and U.S. Pat. No. 4,938,939, entitled“Preparation of Small-pored Crystalline Titanium Molecular SieveZeolites,” name Steve Kuznicki as inventor. Both the '202 patent and the'939 patent are incorporated herein by reference. The '202 patentdiscloses “ETS molecular sieve zeolites.” The '939 patent discloses aclass of compounds referred to as ETS-4 having a pore size of from 3-5Å. Table 1 below provides relative amounts of materials used to prepareETS-4 as per Example 4 in the '939 patent.

TABLE 1 Adsorbent ETS-4 (091504) Reagent Amount Sodium Silicate 25.1grams Sodium Hydroxide  4.6 grams KF  3.8 grams TiCl₃ 16.3 gramsTemperature-Time 150° C./170 hours Ion-Exchange 10 grams ETS-4, 20 gramsBaCl₂, and 40 grams H₂O @ 200° C.

According to the '202 patent and the '939 patent, which sharesignificant common text:

-   -   These titanium silicates have a definite X-ray diffraction        pattern unlike other molecular sieve zeolites and can be        identified in terms of mole ratios of oxides as follows:

1.0±0.25 M_(2/n)O:TiO₂:ySiO₂:z H₂O

-   -   wherein M is at least one cation having a valence of n, y is        from 1.0 to 10.0, and z is from 0 to 100. In a preferred        embodiment, M is a mixture of alkali metal cations, particularly        sodium and potassium, and y is at least 2.5 and ranges up to        about 5.        The '939 patent, column 2, lines 39-50. Moreover, according to        the '939 patent:    -   It should be understood that this X-ray diffraction pattern is        characteristic of all the species of ETS-4 compositions. Ion        exchange of the sodium ion and potassium ions with cations        reveals substantially the same pattern with some minor shifts in        interplanar spacing and variation in relative intensity. Other        minor variations can occur depending on the silicon to titanium        ratio of the particular sample, as well as if it had been        subjected to thermal treatment. Various cation exchanged forms        of ETS-4 have been prepared and their X-ray powder diffraction        patterns contain the most significant lines set forth in Table        1.        The '939 patent, column 4, lines 32-45.    -   Regardless of the synthesized form of the titanium silicate the        spatial arrangement of atoms which form the basic crystal        lattices remain essentially unchanged by the replacement or        sodium or other alkali metal or by the presence in the initial        reaction mixture of metals in addition to sodium, as determined        by an X-ray powder diffraction pattern of the resulting titanium        silicate. The X-ray diffraction patterns of such products are        essentially the same as those set forth in Table I above.        The '939 patent, column 6, lines 4-12.

U.S. Pat. No. 5,989,316, entitled “Separation of nitrogen from mixturesthereof with methane utilizing barium exchanged ETS-4” disclosesbarium-exchanged compositions of ETS-4 which show particular utility ingas separation processes involving the separation of nitrogen from amixture of the same with methane. The barium cation exchange can makethe resulting composition more stable to heating. Heating to elevatedtemperatures is often required to activate the composition for use inadsorption applications.

Depending on synthesis conditions, these and other crystalline titaniummolecular sieve zeolites of the prior art may have comprised fluorineplus possibly other halides prior to ion exchanging the M cations.However, no measurable (significant) halide content remains after theion exchanging.

SUMMARY

Embodiments of crystalline, titanium silicate molecular sieves aredescribed having a formula representing mole ratios of oxides of

nM₁O:TiO₂:ySiO₂:zH₂O:wX

where M₁ refers to at least one metal cation; n is from about 1 to about2; y is from about 1 to about 10; z is from 0 to about 100; X consistsof halide anions other than fluorine; and w is greater than 0. Inparticular, X can be Cl and w can be between about 0.01 and 1.

A process for making crystalline titanium silicate molecular sieves alsois described. One embodiment of the disclosed process for preparing atitanium silicate molecular sieve comprises combining a source ofsilicon, a source of titanium, a source of alkalinity, a metal salt, anda halide anion source other than fluorine. The mole ratio of SiO₂/TiO₂is greater than about 1; H₂O/SiO₂ is greater than about 2; and M₁/SiO₂is from about 0.1 to about 10. M₁ is a metal cation, or mixture ofcations. The composition is processed at a temperature and for a periodof time effective to produce desired titanium silicate molecular sieves.

The process can further comprise performing ion exchange on the titaniumsilicate molecular sieve to produce an ion-exchanged titanium silicatemolecular sieve. This produces an ion-exchanged molecular sieve having aformula representing mole ratios of oxides of

nM₂O:TiO₂:y SiO₂:zH₂O:wX

wherein M₂ is also at least one metal cation and n is from about 1 toabout 2. For particular disclosed embodiments, M₁ can comprise sodiumand/or potassium. Barium can be exchanged for the M₁ cations therebyresulting in M₂ comprising barium, sodium, and potassium. The ionexchange step in the process can be used to adjust the pore size of thetitanium silicate molecular sieve.

Titanium silicate molecular sieves of the present invention also can beused to prepare compositions. For example, such compositions cancomprise a titanium silicate molecular sieve according to the presentinvention, and from greater than zero weight percent to less than onehundred percent of at least one additional material. The at least oneadditional material typically is an inert material, an active material,or combinations thereof, and more specifically typically is a syntheticzeolite, a naturally occurring zeolite, a desiccant, a catalyst, a clay,silica, a metal oxide, or combinations thereof.

Embodiments of adsorbers for use in an adsorption separation processalso are described. For example, the adsorber may comprise an adsorbenthousing or a substrate, and at least one disclosed embodiment of atitanium silicate molecular sieve in the housing or on the substrate.Disclosed adsorbers can be a packed bed comprising the titanium silicatemolecular sieve. Alternatively, the titanium silicate molecular sievemay be on a substrate, such as a flexible substrate that can be spirallywound.

Adsorptive fluid separation processes also are described, comprisingproviding a crystalline titanium silicate molecular sieve and contactingthe molecular sieve with a feed fluid mixture comprising at least afirst component and a second component. This produces at least oneproduct fluid enriched in the first component relative to the secondcomponent. A particular embodiment of a disclosed adsorptive fluidseparation process comprises providing a crystalline titanium silicatemolecular sieve and contacting the titanium silicate molecular sievewith a feed fluid mixture comprising methane to produce at least oneproduct fluid enriched in methane using an adsorption process. Forexample, certain disclosed embodiments of the process concern adsorptiveseparation of carbon oxides [carbon monoxide (CO) and/or carbon dioxide(CO₂)], nitrogen (N₂), oxygen (O₂), and/or hydrogen sulfide (H₂S) toproduce an enriched natural gas product. Such process may be a pressureswing process, a partial pressure swing process, a temperature swingprocess, a vacuum pressure swing process, or combinations thereof.Moreover, the process can be implemented in a rapid cycle pressure swingadsorption device, that is a device capable of operating at cycle speedspreferably in excess of about 1 cycle per minute, even more preferablyin excess of about 5 cycles per minute.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a powder XRD pattern for ETS-4, a prior art material madeaccording to the process described in Example 4 of U.S. Pat. No.4,938,939 and designated as comparative Sample C1 in the Examples.

FIG. 1 b is a powder XRD pattern for one embodiment of a reduced porezorite material of the present invention designated as Sample 1 in theExamples.

FIG. 1 c is a powder XRD pattern for one embodiment of a reduced porezorite material of the present invention designated as Sample 3 in theExamples.

FIG. 1 d is a powder XRD pattern for one embodiment of a reduced porezorite material of the present invention designated as Sample 2 in theExamples.

FIG. 1 e is a powder XRD pattern for one embodiment of a reduced porezorite material of the present invention designated as Sample 4 in theExamples.

FIG. 1 f is a powder XRD pattern for a prior art material designated ascomparative Sample C2 in the Examples.

FIG. 1 g is a powder XRD pattern for one embodiment of a reduced porezorite material of the present invention designated as Sample 5 in theExamples.

FIG. 2 a is a gas chromatogram of the elution of a methane-air mixturethrough comparative Sample C1 in the Examples.

FIG. 2 b is a gas chromatogram of the elution of a methane-air mixturethrough Sample 1 in the Examples.

FIG. 2 c is a gas chromatogram of the elution of a methane-air mixturethrough Sample 3 in the Examples.

FIG. 2 d is a gas chromatogram of the elution of a methane-air mixturethrough Sample 2 in the Examples.

FIG. 2 e is a gas chromatogram of the elution of air through Sample 4 inthe Examples where the single peak shows no separation of nitrogen,oxygen or argon.

FIGS. 2 f-2 o are gas chromatograms of the elution of a methane-airmixture through Samples C3-C7 and 6-10 respectively in the Examples.

FIGS. 2 p-2 y are gas chromatograms of the elution of an argon-oxygenmixture through Samples C3-C7 and 6-10 respectively in the Examples.

FIGS. 2 z-2 ac are gas chromatograms of the elution of a methane-airmixture through Samples 11-14 respectively in the Examples.

FIGs. 2 ad-tag are gas chromatograms of the elution of an argon-oxygenmixture through Samples 11-14 respectively in the Examples.

FIGS. 2 ah-2 ai are gas chromatograms of the elution of an argon-oxygenmixture through Samples 22-23 respectively in the Examples.

FIG. 3 a shows isotherm data for Sample 1 pre-ion exchange.

FIG. 3 b compares isotherm data for Sample C1 to that of Sample 1.

DETAILED DESCRIPTION I. Introduction

Unless expressly defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by a person ofordinary skill in the art to which this disclosure belongs. The singularterms “a,” “an,” and “the” include plural referents unless the contextclearly indicates otherwise. Similarly, the word “or” is intended toinclude “and” unless the context clearly indicates otherwise.

The term “includes” means “comprises.”

pH as used herein either refers to i) when preparing the crystallinemolecular sieve, the pH of the reaction mixture before crystallizationdiluted 100:1 by volume with water and equilibrated for 1 minute; or ii)when ion exchanging cations or anions in the molecular sieve, theas-measured pH value of the solution or slurry.

The separations described herein can be partial, substantial or completeseparations unless indicated otherwise. All percentages recited hereinare weight percentages unless indicated otherwise. In the case ofconflict, the present specification, including explanations of terms,will control.

The materials, methods, and examples described herein are intended to beillustrative only and are not intended to limit the invention to thespecific materials, methods and examples disclosed.

II. Titanium Silicate Molecular Sieves

The present invention concerns titanium silicate molecular sieves. Thesematerials are substantially stable, both chemically and thermally.Moreover, the physical properties of certain embodiments of thematerials, such as pore size and adsorptive characteristics, also aresubstantially stable, even with varying ambient conditions, such astemperature. Certain embodiments of disclosed molecular sieves aremetal-exchanged titanium silicates. And, most adsorptive separationembodiments use crystalline phases of the disclosed titanium silicatemolecular sieves.

Zeolites typically have been considered to be crystalline, porousaluminosilicates. Relatively recent discoveries of materials virtuallyidentical to the classical zeolite, but comprising structures withelements other than silicon and aluminum, have stretched the definition.Most researchers now define zeolite to include virtually all types ofporous oxide structures that have well-defined pore structures due to ahigh degree of crystallinity. Typically, the metal atoms (classically,silicon or aluminum) are surrounded by four oxygen anions to form anapproximate tetrahedron consisting of a metal cation at the center andoxygen anions at the four apexes. The tetrahedral metals, called T-atomsfor short, stack in regular arrays to form channels. The stackingpossibilities are virtually limitless, and more than a hundred uniquestructures are known. Titanium silicate molecular sieves of the presentinvention do not necessarily include tetrahedrally coordinated metalatoms, such as titanium, and instead certain embodiments may bemixed-coordination materials where metal atoms may be in coordinationstates other than tetrahedral.

The structure of channels (or pores) are nanoscopically small, and havemolecular-size dimensions such that they often are termed “molecularsieves.” Without being bound by a theory of operation, as currentlyunderstood the size, shape, and electric charge potential of thechannels determine the properties of these materials, which allows thematerials to be used for various purposes, including adsorptionseparation processes. Molecules can be separated, for example, viashape, size effects related to their possible orientation in the pore,and/or by differences in strength of adsorption.

A. Compositions of Titanium Silicate Molecular Sieves

Certain disclosed embodiments of titanium silicate molecular sieves ofthe present invention typically have molecular compositions where themole ratios of oxides are as indicated by the following formula.

nM₁O:TiO₂:ySiO₂:zH₂O:wX

With reference to this formula, M₁ refers to a metal cation or mixtureof metal cations, n can range from about 1 to about 2; y is from about 1to about 10 more typically at least 2 and up to about 5; z is from 0 toabout 100, more typically from about 5 to about 60, even more typicallyfrom about 5 to about 40; X is a halide anion or mixture of halideanions other than fluorine, and w is greater than 0, typically betweenabout 0.01 and about 1.

The general formula provided above describes the genus of titaniumsilicate molecular sieves of the present invention. A person of ordinaryskill in the art will appreciate that general formulae describingsub-genera within the broad genus also are possible.

This general formula applies to compounds made both with and withoutcation exchange. Prior to exchange, M₁ typically is a Group I metal ion(or ions) that is provided by an alkaline metal compound, such as aGroup I metal hydroxide, typically sodium or potassium hydroxide. Theinitial cation, or mixture of cations, that are provided by initialreactants prior to conducting an exchange reaction can be replaced, atleast in part or substantially completely, with other cations usingcation exchange techniques. Working examples of cation exchangereactions are further disclosed in the Examples below. Thus, for thesemetal-exchanged titanium silicate molecular sieves, suitable replacingmetals include metals of IUPAC classification Groups 1-3 metals, Group8-12 metals, alkaline earth metals, rare earth metals, and allcombinations thereof. A currently preferred group of metals for exchangewith, for example, sodium and/or potassium in a non-exchanged titaniumsilicate molecular sieve is barium, calcium, potassium, strontium,magnesium and silver. A currently preferred metal is barium, whichprovides good thermal stability in compounds made to date.

It also is possible to conduct other types of exchange reactions thatexchange positively-charged materials (other than metals) for metalssuch as sodium and/or potassium that are present in disclosed titaniumsilicate molecular sieves prior to exchange reactions. For example,typical replacing components would include, but are not limited to,hydrogen, ammonium, aliphatic ammonium, most typically alkyl ammonium,aryl ammonium, metals, and mixtures thereof.

B. Ordered Crystal Structure and XRD Patterns

X-ray diffraction is primarily used to determine atomic arrangements incrystalline materials. “Crystal” refers to a region of matter withinwhich the atoms are arranged in a three-dimensional, translationallyperiodic pattern, which is referred to as the crystal structure.

A lattice is an imaginary pattern of points (or nodes) in which everypoint (node) has an environment that is identical to that of any otherpoint (node) in the pattern; it has no specific origin, as it can beshifted parallel to itself. Lattice points can be notated using acrystal coordinate system. A point in the lattice is chosen as theorigin and is defined as 000. The a, b and c axes define directionswithin the crystal structure, with the angular relations thereof beingdefined by a particular crystal structure.

Lattice planes are defined in terms of Miller Indices, which arereciprocals of the intercepts of the planes on the coordinate axes. AMiller index refers to a family of parallel lattice planes defined by afixed translation distance (defined as d) in a direction perpendicularto the plane. The perpendicular distances separating each lattice planein a stack is denoted by the letter d, and are referred to as dspacings, which can be used to describe peaks in an XRD pattern.

The titanium silicate molecular sieves of the present invention areeither produced in crystalline form, or can be produced amorphous andsubsequently crystallized. In the below Examples, XRD patterns for ETS-4materials (i.e. zorite) produced according to the '939 patent have beencompared to titanium silicate molecular sieves of the present inventionusing the same XRD device. The crystal structure of the presentmolecular sieves have substantially similar lattice spacings to thezorite. However, in some embodiments and unlike that of zorite, thepresent molecular sieves can have an XRD pattern in which at least onepeak has an intensity greater than an intensity of a peak at a d-spacingof 6.96 Å.

For ETS materials, no other peak in the XRD pattern is more intense,i.e. higher, than the peak at a d-spacing of about 7 Å, and hence thispeak was selected to be the reference peak. It is typical to normalizeall peak intensities in an XRD pattern to a reference peak. Therefore,all other peaks in XRD patterns used to compare titanium silicatemolecular sieves of the present invention to the ETS materials of the'202 and '939 patents were normalized to the reference peak at ad-spacing of about 7 Å.

C. Pore Size of Disclosed Molecular Sieves Materials made according tothe present invention have a pore size that (1) is stable, and (2) canbe varied within a pore size range to provide a pore size effective forperforming a particular purpose, such as for adsorptive fluidseparations. This pore size range typically varies from a pore size ofgenerally greater than about 2 Å to at least about 5 Å, and moretypically from about 2.5 Å to about 4.5 Å. These pore sizes are deducedfrom empirical studies based on fluid separations of molecules of knownsizes. For instance, the molecular diameter of various gases is given inZeolite Molecular Sieves, by D. W. Breck, reprinted 1984. If anadsorbent material is then capable of separating two gases of differingmolecular diameter (e.g. one gas is adsorbed while the other is not), itis deduced that the pore diameter of the adsorbent material liessomewhere between the molecular diameters of the two gases.

As an example, certain embodiments of the present molecular sieves, suchas a molecular sieve comprising chloride anions and having initial IUPACclassification Group I metal ions, such as sodium ions, at leastpartially exchanged with barium cations, have been brought into contactwith a fluid stream comprising a fluid mixture of nitrogen and methaneand to enrich a fluid product stream in a desired component, such asmethane. These particular titanium silicate molecular sieve embodimentspreferentially adsorb nitrogen. Separating nitrogen from methane in afluid mixture comprising the two based on size is a relatively difficultseparation as nitrogen has a diameter of about 3.6 Å, and methane has adiameter of about 3.8 Å. The pore size of these particular sieveembodiments then is deduced to be between 3.6 Å and 3.8 Å.

Pore size also has been deduced by water molecule adsorption trials.Water has a mean van der Waals diameter of about 2.82 Å. Titaniumsilicate molecular sieves made according to working embodiments of thepresent invention but prior to any exchange reaction, typically havesmall pores that adsorb only water molecules. Metal exchanged titaniumsilicate molecular sieves may have larger pore sizes. Divalentmetal-exchanged titanium silicate molecular sieves typically have largerpore sizes than the as-made compositions.

Thus, a person of ordinary skill in the art will appreciate thattitanium silicate molecular sieves of the present invention are highlyadsorptive toward molecules of a particular size range. This size rangevaries from at least about 2 Å up to approximately 5 Å, more typicallyfrom about 3 Å to about 4.5 Å in diameter. As a result, these titaniumsilicate molecular sieves are substantially non-adsorptive to moleculeshaving effective diameters larger than about 5 Å in critical diameter.

The utility of a particular titanium silicate molecular sieve depends,at least in part, on the composition of a fluid mixture contacting themolecular sieve. The titanium silicate molecular sieve is most efficientif its pore size is tailored for selective adsorption of a particularconstituent of a fluid mixture. Thus, one beneficial aspect of thepresent invention is the ability to control pore size through a varietyof mechanisms.

A first, new and surprising method for controlling pore size is throughthe incorporation of halide anions other than fluorine in the molecularsieves. This is accomplished via suitable selection of halide anionspresent in the synthesis mixture, and hence reagents suitable forproviding such anions, that are used to form the titanium silicatemolecular sieves. In particular, the halide anion can be chlorine.

Pore size can however be varied by selecting different halide species orcombinations of halide species that do not include fluorine. Forexample, working embodiments of new titanium silicate molecular sieveshave been produced by using different halide anions, typically titaniumsilicate molecular sieves where the halide is chloride or iodide.Bromide is also expected to be a useful anion choice. A series ofbarium-sodium exchanged titanium silicate molecular sieves have beenmade using various halides. Barium-exchanged, titanium silicatemolecular sieves containing iodide, for example, may adsorb onlymolecules that are as small as carbon dioxide or smaller, i.e. about 3.3Å or smaller. Barium-exchanged, titanium silicate molecular sievescontaining chloride had larger pore sizes, about 3.7 Å, and are usefulfor separating, for example, methane from a fluid mixture comprisingboth methane and nitrogen. Prior art, barium-exchanged, titaniumsilicate molecular sieves synthesized with only potassium fluoride addedto the synthesis mixture appear to have the largest pore size, i.e.about 3.7 Å to about 4.0 Å, within the family of barium-sodium exchangedtitanium silicate molecular sieves made. Some anion sources mayintroduce hydroxyl anions into the framework. This may affect the poresize of the adsorbent.

A second method for controlling pore size is to control processingparameters such as temperature and pH. For example, the pH of thesynthesis mixture can be adjusted to facilitate production of titaniumsilicate molecular sieves of varying pore sizes. Working embodiments ofthe present invention have adjusted the pH of a processing solution froma first pH of about 10.5 to about 13, to provide a variation in poresize of from about 0.1 Å to about 0.5 Å. Alternatively, the pH of theion-exchange solution can be adjusted to control the pore size of theexchanged material. The pH of the exchange solution is limited by thestability of the material to the condition of the solution.Titanosilicate molecular sieves are significantly more acid resistantcompared to conventional aluminosilicate molecular sieves. As a result,inventive materials examined to date have displayed stability toexchange solutions having a pH between 2 and 13.

Certain embodiments of titanium silicate molecular sieves of the presentinvention, particularly rare earth-exchanged titanium silicate molecularsieves, even more particularly barium-exchanged titanium silicatemolecular sieves, have a high degree of thermal stability at atemperature of at least as high as about 200° C., preferably at least ashigh as about 300° C., even more preferably at least as high as about400° C., and yet even more preferably to a temperature of at least ashigh as 450° C. These materials therefore are effective for use in hightemperature catalytic processes. Furthermore, because these titaniumsilicate molecular sieve embodiments have framework stability at theseelevated temperatures, the pore size of the as-synthesized materialremains substantially constant throughout this temperature range aswell.

However, other embodiments of titanium silicate molecular sieves withinthe scope of the present invention change pore size with temperaturechanges, such as by contracting during a heating cycle. The pore sizealso typically changes substantially uniformly over the temperatureheating range. As a result, heating is another example of a processvariable that can be used to vary pore size of disclosed titaniumsilicate molecular sieves. Thus, a desired pore size can be obtained bycontrolling process temperature, and can be determined, for example, byproviding or consulting a pore size versus temperature plot. Heatingtemperatures between about 100° C. and about 500° C. provide materialshaving suitable pore sizes.

Yet another, and particularly useful, method for controlling pore sizeof exchanged materials is to control the degree of metal exchange, orthe exchange mixture of cations. For example, if a titanium silicatemolecular sieve is subjected to barium metal exchange, then the absolutedegree of barium exchange for a particular cationic metal, such aspotassium or sodium, can vary as discussed herein. Similarly, therelative amounts of the mixture of initial ions, sodium and potassiumfor example, also can vary. Pore size also can be adjusted bycontrolling the exchange reaction(s).

It has been observed that the anion species previously incorporated inthe material can be lost as a result of ion exchanging the cationspecies. However, the rate at which the anion species is lost or removedduring a given cation exchange process seems much reduced in the presentmaterials as compared to the rate of anion loss in prior art materialssynthesized using potassium fluorine as an anion source in the synthesismixture. This decreased rate of anion loss enhances the ability tocontrol the pore size of the adsorbent.

III. General Synthetic Approach

A. Titanium Silicate Molecular Sieves

Titanium silicate molecular sieves of the present invention can beprepared from a reaction mixture containing suitable sources of eachreagent used in amounts effective to produce desired materials. Forexample, the molecular sieves of the present invention typically aretitaniumsilicates. The reaction mixture used to make such molecularsieves therefore includes a source of titanium and a source of silicon.Suitable sources of titanium include titanium salts, such as halidesalts, carbonate salts, sulfate salts, nitrate salts, phosphate salts,and combinations thereof. A person of ordinary skill in the art willappreciate that other counter anions also potentially can be used.

The reaction mixture also typically includes a reactive source ofsilicon. Examples of suitable sources of silicon include, but are notlimited to, silica, silica hydrosol, silica gel, silicic acid, alkoxidesof silicon, alkali metal silicates, preferably sodium or potassiumsilicates, and mixtures of these silicon sources.

The reaction mixture also typically includes a suitable source ofalkalinity. Typically this is provided by an alkali metal hydroxide,preferably an aqueous solution of an alkali metal hydroxide, such assodium hydroxide or potassium hydroxide. This reagent provides a sourceof alkali metal ions for maintaining electrovalent neutrality in thecrystallized product. It also controls the pH of the reaction mixturewithin a range effective to produce desired compounds, such as a pHrange of from about 10.5 to about 13, more typically from about 10.8 toabout 11.5.

Appropriate materials, such as a source of titanium, a source ofsilicon, a suitable source of alkalinity, and a source of halide anionsother than fluorine, are combined to form a reaction mixture comprisingrelative amounts of each reagent effective to produce desired compounds.The synthesis of such materials is not significantly dependent on thequantity of silica or water in the system. In systems containing largeamounts of silica, the unreacted amount is filtered and washed away fromthe crystallized adsorbent. It is also possible to synthesize zeolitesand other microporous materials from solutions containing large amountsof water (H₂O:TiO₂>100). The amount of adsorbent crystallized from sucha reaction would be lower than from a reaction containing less water butlarge H₂O:TiO₂ ratios do not necessarily inhibit the synthesis of thetarget molecular sieve. Effective relative mole ratios of each reagentcan be determined empirically, but for working examples generally havebeen substantially equal molar amounts, perhaps with a slight excess ofthe reagent providing a source of alkalinity. More specifically, andwith reference to working embodiments, about 0.1 mole of a suitablesource of silicon, about 0.02 mole of a suitable source of titanium, andabout 0.11 mole of a suitable source of alkalinity have been used.Working embodiments also include a suitable source of a halide anion,that has varied in such working embodiments from an amount greater thanabout 0.01 mole to about 0.1 mole, more typically greater than about0.02 mole to about 0.08 mole, and even more typically from about 0.04 toabout 0.06 mole.

The reaction mixture is heated at a temperature, and for a period oftime, suitable to produce desired compounds. For working embodiments,the processing temperature typically varied from greater than ambient toat least as high as about 300° C., more typically from about 50° C. toabout 250° C., and even more typically from about 100° C. to about 225°C.

The reaction period generally is a few hours up to a period of manydays. More typically the reaction period ranges from about 8 hours toabout 48 days, and even more typically from about 8 hours to about 48hours. The reaction may result in the production of a crystallineproduct. Thus, another method for determining the reaction period is toallow the reaction to continue until crystals are formed. The resultingcrystalline product is thereafter separated from the reaction mixture,cooled to room temperature, filtered and water washed. The reactionmixture can be stirred, although it is not necessary to do so.

Titanium silicate molecular sieves of the present invention can beamorphous, and thereafter crystallized, or can be crystalline, andrecrystallization used to enhance, for example, product purity.Crystallization can be performed either as a continuous process, or as abatchwise process under autogeneous pressure in an autoclave or staticpressure vessel. Isolated crystalline products typically are washed,such as by using a water washing step, and then dried at a suitabledrying temperature for a period of time effective to provide the desiredlevel of product hydration, such as a drying temperature of greater thanabout 100° C. to at least about 300° C., and typically a dryingtemperature of about 275° C. The heating process continues for as longas is required to obtain a product with a desired water content, whichranges from as low as is technically and commercially feasible in such amaterial, e.g. 0.01 weight percent to about 5 weight percent. Titaniumsilicate molecular sieves of the present invention may includesignificant amounts of moisture in the framework and still be effectivefor use in adsorption separation processes. By way of comparison, awater content of about 0.5% typically reduces the effectiveness of knownzeolites for use in adsorption separation processes.

B. Exchange Reactions

Titanium silicates as synthesized can have the original componentsthereof replaced or exchanged using techniques known in the art.Cationic components, such as metal atoms, are typical exchangecandidates. Typical classes of reagents used for positive ion exchangereactions include, but are not limited to, hydrogen, ammonium, alkylammonium, aryl ammonium, metals, and mixtures thereof. Metals are acurrently preferred class of reagents used for exchange reactions.Suitable replacing metals include, without limitation, metals of IUPACClassification Groups 1-3 and 8-12 of the Periodic Table, the rare earthmetals, and preferably the alkaline earth metals beryllium, magnesium,calcium, strontium and barium, with barium being a currently preferredmetal for conducting exchange reactions.

For working embodiments exemplified by barium exchange, a non-exchangedtitanium silicate molecular sieve is first produced as disclosed herein.A mixture is then formed comprising a suitable source of barium, such asa metal halide, for example barium chloride (BaCl₂) and thenon-exchanged titanium silicate molecular sieve. The mixture can beformed as a dry mixture, and then added to water, or can be addedindividually to water to form an aqueous composition. The relativeamounts for these reagents can be varied, as will be appreciated by aperson of ordinary skill in the art, to vary the amount of metal-metalexchange, but such amounts typically range from weight ratios of about1:1 to about 2:1 barium exchange material to non-exchanged titaniumsilicate molecular sieves. The aqueous composition is then exposed to atemperature, and for a period of time, effective to produce desiredcompounds. For example, working embodiments typically refluxed theaqueous composition at 100° C. for about 1 hour or more. Alternatively,the mixture can be charged in an autoclave and heated at temperatures ofat least 100° C. for at least one hour.

The amount of halide anion present in the molecular sieve can have aninfluence on the pore size of the adsorbent and compositions of thepresent invention show correlations between halogen content andeffective pore size.

C. Post Formation Processing

Compositions made according to the present invention can be subjected toadditional post synthesis processing. For example, such compositions canbe calcined at an effective calcining temperature that, for workingembodiments, was within a temperature range of from about 500° F. to atleast about 1,500° F., and more typically was about 1,000° F. Calciningcontinues for periods of time ranging from about 1 to at least as longas about 48 hours. This results in ammonia evolution and hydrogenretention in the composition, i.e., hydrogen and/or decationized form.Calcining can be performed in air or an inert atmosphere.

The crystalline titanium silicates also can be washed, typically withwater, and then dried at an effective drying temperature, whichtypically ranges from about 150° F. to about 600° F., before calcining.

IV. Titanium Silicate Molecular Sieves Form and Particle Size

Titanium silicate molecular sieves prepared in accordance with theinvention are formed in a wide variety of particle sizes. Generally, theparticles can be a powder, a granule, or a molded product, such as anextrudate. The titanium silicate molecular sieves can be size classifiedusing a screen. Typically, as formed, titanium silicate molecular sievesof the present invention have a particle size sufficient to pass througha 2 mesh (Tyler) screen and be maintained on a 400 mesh (Tyler) screen,particularly where the molecular sieve is molded, such as by extrusion.The titanium silicate can be extruded before drying or dried orpartially dried and then extruded.

V. Compositions Comprising Titanium Silicate Molecular Sieves

Titanium silicate molecular sieves of the present invention can be usedwithout being formulated with other materials. Alternatively, titaniumsilicate molecular sieves of the present invention can be used to formcompositions suitable for desired applications. For example, titaniumsilicate molecular sieves of the present invention can be combined withanother material, or materials, resistant to the temperatures and otherconditions employed in particular processes. Such materials includeactive and inactive materials, synthetic and naturally occurringtitanium silicate molecular sieves, as well as inorganic materials, suchas clays, silica and/or metal oxides. Active materials also can be usedin conjunction with the titanium silicate molecular sieves of thepresent invention to, for example, improve the conversion and/orselectivity of the molecular sieves. Inactive materials suitably serveas diluents to control the amount of conversion in a given process sothat products can be obtained economically and in an orderly mannerwithout employing other means for controlling the reaction rate.

Titanium silicate molecular sieves of the present invention also can beincorporated into naturally occurring clays, e.g., bentonite and kaolin,to improve certain physical properties, such as crush strength, of thecatalyst under commercial operating conditions. Examples of naturallyoccurring clays that can be used to form compositions comprisingtitanium silicate molecular sieves of the present invention include themontmorillonite and kaolin families, which include the sub-bentonitesand the kaolins commonly known as Dixie, McNamee, Georgia and Florida,or others in which the main constituent is halloysite, kaolinite,dickite, nacrite or anauxite. Such clays can be used with or withoutcalcination, acid treatment and/or chemical modification.

Titanium silicate molecular sieves of the present invention also may becomposited with a porous matrix material. Exemplary porous matrixmaterials include silica-alumina, silica-magnesia, silica-zirconia,silica-thoria, silica-berylia, silica-titania, as well as ternarycompositions, such as silica-alumina-thoria, silica-alumina-zirconia,silica-alumina-magnesia and silica-magnesia-zirconia. The relativeproportions of titanium silicate molecular sieves of the presentinvention and other materials can vary widely with the crystallineorganosilicate content ranging from greater than about 1 percent to 100percent by weight, typically from greater than 1 percent to at least 90percent by weight, and more typically from about 2 to about 50 percentby weight of the composite.

Additional information concerning compositions useful for adsorptionseparations processes can be found in patents and publishedapplications, including U.S. Pat. No. 6,692,626, application Ser. No.10/041,536, entitled “Adsorbent Coating Compositions, Laminates andAdsorber Elements Comprising such Compositions and Methods for theirManufacture and Use,” and international application No.PCT/US2004/032067, entitled “High Density Adsorbent Structures,” each ofwhich is incorporated herein by reference.

VI. Adsorbent Beds and Adsorbers Comprising Disclosed Titanium SilicateMolecular Sieves

One primary use for the present titanium silicate molecular sieves isadsorptive fluid separation processes. The titanium silicate molecularsieves can be used as packed beds, or can be used to make adsorbers oradsorber elements. Exemplary adsorbers and adsorber elements aredisclosed in patents and published applications referred to herein. Forexample, certain embodiments of the present invention are designed foruse with pressure swing adsorption separation processes. These processescan be practiced using packed beds of disclosed titanium silicatemolecular sieves, both alone and in combination, generally as separatelayers or regions, with other inert and/or active materials.

Particular applications concern rotary pressure swing adsorptionapplications. For these applications, present titanium silicatemolecular sieves may be used to form adsorbent sheets, such as disclosedin cited patent documents that are incorporated herein by reference.

Without being bound by theory, the molecular sieves of the invention arebelieved to differ from prior art zorite compositions in that the formercomprise halide anions other than fluorine in their structure.Zorite-type materials have 8-membered rings that connect to form linearchannels through the crystalline structure. Titanium atom chains areprovided down the length of these channels. The chains have terminalgroups that protrude into the channels. In conventional zoritematerials, these Ti atoms terminate with —OH (hydroxyl) groups. However,for molecular sieves of the present invention, it is speculated that theOH groups are at least partially substituted by Cl or other non-fluorinehalogens. These halogens are larger in diameter than the hydroxyl and Fgroups and will thus effectively reduce the pore size by providing abarrier to diffusion of gas molecules into the pores and channels. Thegreater the amount of halogens present in the material, the smaller theeffective pore and the higher the barrier to adsorption. It is furtherbelieved that the type and quantity of halogens determines the effectivepore size while the type and quantity of cation determines the thermalstability and gas capacity of the molecular sieves of the invention.

Prior art zorite materials on the other hand typically do not containany halogens in their structure. Certain materials had been preparedusing fluorine-containing reactants (e.g. KF) and fluorine may have beenincorporated into the material. However, fluorine is rapidly removed byconventional cation exchange processing and thus even fluorine is nottypically retained in prior art zorite materials. It is noteworthy thatpast x-ray crystallography studies have solved the structures of priorart write-related molecular sieves and none indicates the presence ofhalide in the molecular sieve. Further, chemical analysis associatedwith the crystallographic studies of ETS-4 indicated that no halideswere present and that seemingly equivalent samples of ETS-4 could bemade using synthesis mixtures which either contained halides or didn'tcontain halides (e.g. synthesis involving TiCl₃ versus TiOSO4). See, forinstance, the aforementioned U.S. Pat. No. 5,989,316.

VII. Examples

The following examples are provided to exemplify particular features ofthe present invention. A person of ordinary skill in the art willappreciate that the scope of the present invention is not limited to theparticular features exemplified by these examples.

Various reduced-pore zorite (RPZ), titanium silicate molecular sieveadsorbent samples were prepared in accordance with the invention.Several physical characteristics were measured and their ability toseparate certain gas mixtures was determined. For comparative purposes,prior art ETS-4 type adsorbent materials were also prepared and analyzedin a like manner. Table 3 summarizes some of the key process parametersused to prepare the samples, along with the characteristics andproperties of the prepared samples.

In Table 3, Samples are listed in chronological order ofcharacterization. Samples C1 and C2-7 are comparative, prior art,ETS-type materials. The other Samples are materials of the presentinvention. Ba-exchanged samples referred to in applicants' priorprovisional application No. 60/817,536, namely Ba—RPZ(a), Ba—RPZ(b),Ba—RPZ(c), Ba—RPZ(d), have been renamed here as Samples 1, 3, 2, and 4respectively.

A. Preparation

In all cases, samples were prepared using reagents and proceduressimilar to those listed in Table 2, which shows the specific details forthe preparation of Sample 1. For all the Samples, a crystalline materialof the form nM₁O:TiO₂:y SiO₂:zH₂O:wX was initially prepared. In most butnot all cases, the material was then subjected to an ion exchangereaction such that a certain amount of Ba was exchanged for cations M₁in the precursor materials.

Sample 1 was prepared in the following manner. 25.1 grams of sodiumsilicate, 4.6 grams of sodium hydroxide, 3.0 grams of KCl and 16.3 gramsof TiCl₃ solution were combined and processed in an autogenous pressureautoclave for 48 hours at 200° C. to produce a crystalline precursormolecular sieve material. The crystalline precursor material was washedand dried. An ion exchange reaction was then conducted by providing anaqueous mixture comprising 10 grams of precursor molecular sievematerial, 20 grams of BaCl₂, and 40 grams of water for a period of timewithout stirring. The aqueous mixture was then heated at 200° C. to formthe barium exchanged titanium silicate molecular sieve Sample 1.

TABLE 2 Sample 1 pre-ion exchange Reagent Amount Sodium Silicate 25.1grams Sodium Hydroxide  4.6 grams KF KCl  3.0 grams Kl — TiCl₃ 16.3grams Temperature-Time 200° C./48 hours Sample 1 Ion-Exchange 10 gramsSample 1 pre-ion exchange, 20 grams BaCl₂, and 40 grams H₂O @ 200° C.

Table 3 below provides, inter alia, additional samples, productionconditions, composition, etc.

TABLE 3 Table Halide Ion Exchange Stirring Sample salt Exchange ParentTemp Exchange Ion Exchange during ID additive agent sample (° C.) timepH exchange? C1 KF BaCl₂ 200 Not NC No controlled (NC)  1 KCl BaCl₂ 200NC NC N  2 KCl BaCl₂ 5/10/40 g 100 NC NC N (sample/BaCl₂/H₂0)  3 KClBaCl₂ 5/10/40 g 100 NC NC N (sample/BaCl₂/H₂0)  4 KI BaCl₂ 5/10/40 g 100NC NC N (sample/BaCl₂/H₂0) C2 KF None — — — — NA C3 BaCl₂ C2  2 hrs NC NC4 BaCl₂ C2  4 hrs NC N C5 BaCl₂ C2 100  8 hrs NC N C6 BaCl₂ C2 100 16hrs NC N C7 BaCl₂ C2 100 24 hrs NC N  5 KCl none — — — — NA  6 BaCl₂ 5100  2 hrs NC N  7 BaCl₂ 5 100  4 hrs NC N  8 BaCl₂ 5 100  8 hrs NC N  9BaCl₂ 5 100 16 hrs NC N 10 BaCl₂ 5 100 24 hrs NC N 11 21 mole eq BaCl₂ 5100  8 hrs NC Y 12  7 mole eq BaCl₂ 5 100  8 hrs NC Y 13 21 mole eqBaCl₂ 5 ambient  8 hrs NC Y 14  7 mole eq BaCl₂ 5 ambient  8 hrs NC Y 15BaCl₂ 5 100 72 hrs NC N 16 BaCl₂ C2 100 72 hrs NC N 17 BaCl₂ 5 100  1week NC N 18 BaCl₂ C2 100  1 week NC N 19 BaCl₂ 5 100 10 days NC N 20BaCl₂ C2 100 10 days NC N 21 KCl none — — — — NA 22 BaCl₂ 21  ambient  8hrs pH 8 Yes 23 BaCl₂ 21  ambient  8 hrs pH 13 Y 24 BaCl₂ 21  100 24 hrsNC Y 25 BaCl₂ C2 ambient  8 hrs pH 7 Y 26 BaCl₂ C2 200 16 hrs NC N 27BaCl₂ 21  200 16 hrs NC N 28 KI none — — — — 29 KI none — — — — 30 KInone — — — — As- Table synth. Sample XRD Composition Gas ID data(byEDX/EMP) excluded GC plots obtained C1 Yes Not available  1 Y 1.09Ba0.1Na 0.05K 2.46SiO₂ 1TiO₂ 0.07Cl CH₄ methane/air  2 No 0.97Ba 0.13Na0.07K 2.4SiO₂ 1TiO₂ 0.01Cl CH₄ methane/air  3 N 1.09Ba 0.19Na 0.05K2.44SiO₂ 1TiO₂ 0Cl CH₄ methane/air  4 Y Not available C2 Y 1.12Na 0.41K2.22SiO₂ 1TiO₂ 0.03Cl 0.32F none C3 0.86Ba 0.25Na 0.13K 2.28SiO₂ 1TiO₂0Cl CH₄ air; CH₄; air/CH₄; Ar; O₂; Ar/O₂; C4 0.92Ba 0.17Na 0.09K2.28SiO₂ 1TiO₂ 0Cl CH₄ air; CH₄; air/CH₄; Ar; O₂; Ar/O₂; C5 0.96Ba0.17Na 0.07K 2.39SiO₂ 1TiO₂ 0Cl CH₄ air; CH₄; air/CH₄; Ar; O₂; Ar/O₂; C60.94Ba 0.14Na 0.07K 2.32SiO₂ 1TiO₂ 0Cl CH₄ air; CH₄; air/CH₄; Ar; O₂;Ar/O₂; C7 0.96Ba 0.15Na 0.06K 2.33SiO₂ 1TiO₂ 0Cl CH₄ air; CH₄; air/CH₄;Ar; O₂; Ar/O₂;  5 Y 0Ba 1.55Na 0.45K 2.68SiO₂ 1TiO₂ 0.09Cl none  60.68Ba 0.88Na 0.22K 2.9SiO₂ 1TiO₂ 0.02Cl O₂ air; CH₄; air/CH₄; Ar; O₂;Ar/O₂;  7 0.85Ba 0.59Na 0.18K 2.71SiO₂ 1TiO₂ 0.02Cl O₂ air; CH₄;air/CH₄; Ar; O₂; Ar/O₂;  8 1.1Ba 0.43Na 0.11K 2.86SiO₂ 1TiO₂ 0.02Cl Arair; CH₄; air/CH₄; Ar; O₂; Ar/O₂;  9 1.13Ba 0.39Na 0.1K 2.91SiO₂ 1TiO₂0.01Cl Ar air; CH₄; air/CH₄; Ar; O₂; Ar/O₂; 10 1.21Ba 0.38Na 0.08K3.02SiO₂ 1TiO₂ 0.02Cl CH₄ air; CH₄; air/CH₄; Ar; O₂; Ar/O₂; 11 1.17Ba0.27Na 0.08K 2.7SiO₂ 1TiO₂ 0.01Cl CH₄ Air; CH₄/O₂; Ar/O₂; Ar; CH₄ 12 1Ba0.45Na 0.14K 2.85SiO₂ 1TiO₂ 0.004Cl CH₄ Air; CH₄/O₂; Ar/O₂; Ar; CH₄ 130.28Ba 1.02Na 0.37K 2.67SiO₂ 1TiO₂ 0.02Cl Ar Air; CH₄/O₂; Ar/O₂; Ar; CH₄14 0.26Ba 1.06Na 0.38K 2.79SiO₂ 1TiO₂ 0.02Cl Ar Air; CH₄/O₂; Ar/O₂; Ar;CH₄ 15 1.25Ba 0.36Na 0.08K 2.99SiO₂ 1TiO₂ 0.03Cl none 16 0.99Ba 0.17Na0.08K 2.45SiO2 1TiO2 none 0.01Cl 17 1.31Ba 0.43Na 0.08K 3.3SiO₂ 1TiO₂0.04Cl none 18 0.96Ba 0.18Na 0.08K 2.48SiO₂ 1TiO₂ 0.02Cl none 19 1.26Ba0.36Na 0.08K 3.08SiO2 1TiO2 none 0.04Cl 20 0.93Ba 0.19Na 0.08K 2.44SiO₂1TiO₂ 0.02Cl none 21 Y 0Ba 1.58Na 0.46K 2.88SiO₂ 1TiO₂ 0.05Cl none 220.36Ba 1.15Na 0.36K 3.03SiO₂ 1TiO₂ 0.04Cl O₂ air; CH₄; Ar/O₂; 23 0.36Ba1.3Na 0.42K 2.92SiO₂ 1TiO₂ 0.04Cl Ar air; CH₄; Ar/O₂; 24 1.2Ba 0.33Na0.08K 3.25SiO₂ 1TiO₂ 0.03Cl Ar air; CH₄; Ar/O₂; 25 0.23Ba 0.86Na 0.37K2.48SiO₂ 1TiO₂ 0.03Cl O₂ air; CH₄; Ar/O₂; 26 1.11Ba 0.1Na 0.05K 2.53SiO₂1TiO₂ 0.04Cl none 27 1.38Ba 0.13Na 0.03K 3.02SiO₂ 1TiO₂ 0.07Cl none 28 Y1.58Na 0.41K 2.84SiO₂ 1TiO₂ 0.03Cl 0.01I none 20 Y 1.77Na 0.54K 3.36SiO₂1TiO₂ 0.02Cl 0.004I none 30 Y 1.44Na 0.59K 2.88SiO₂ 1TiO₂ 0.03Cl 0.014Inone

All of the samples listed in Table 3 were prepared in a similar mannerbut for the following exceptions. For some samples, a differentpotassium halide salt (i.e. KCl, KI, or KF) was used in the preparation.The salt employed is indicated in the “Halide salt” column. Sample 4 wasprepared using 10.8 grams of KI at 225° C./16 hours. Sample 28 wasprepared using 6.68 g KI at 215° C. Sample 29 was prepared using 6.68 gKI and 225° C. Sample 30 was prepared using 10.87 g KI at 215° C.

Also, where indicated for certain samples listed in Table 3, no Ba ionexchange was conducted. Generally, different Ba ion-exchange conditionswere employed in the case of the remaining samples, although in allcases the agent used was BaCl₂. Where applicable, Table 3 lists if adifferent concentration of BaCl₂ was used, and also lists thetemperature, time, and pH of the ion-exchange reaction. Also, in somecases, the ion exchange mixture was stirred during the exchange reactionand this too is indicated in Table 3.

As mentioned above, Samples C1 and C2-7 represent prior art compounds.These compounds were prepared for comparative purposes using the priorart method employing KF, a fluorine-containing halide salt, in thepreparation.

B. Characterization

Except where noted, the chemical compositions of all the Samples weredetermined. This was done using EDX/EMP (energy dispersiveX-ray)/(electron microprobe) elemental analysis. All ion-exchangedsamples were subsequently washed with copious amounts of water to ensurethat they were free of residual salts. Thin wafers of samples wereproduced using a pelletization apparatus and mounted to conventional SEMsample stubs. Measurements were made typically in 3 different locationsat 1000 times magnification. The average value over the 3 locations wasdetermined and this was used to determine the composition reported inTable 3. The fluorine content reported on for comparative Sample C2 wasobtained from a similarly prepared, but not the same, sample material.Fluorine is a light element and there is significant error in theindicated fluorine content. None of the other Samples had any detectablefluorine content. The composition of the precursors for Samples 1-4(i.e. prior to ion exchange) was not determined at the time and thusthese precursor Samples were omitted from Table 3.

Where indicated, powder X-ray diffraction patterns were obtained forSamples prior to carrying out any ion exchange in the preparation.Patterns were obtained prior to ion exchange for purposes of directcomparison to patterns of prior art ETS-4 materials which also had notundergone any ion exchange. All XRD analyses discussed herein werecollected using Co K-alpha radiation on a Rigaku Geigerflex 2173 XRDunit equipped with a graphite monochromator.

Also, where indicated, inverse gas chromatograms were obtained of theelution of certain gas mixtures through the Samples. Inverse gaschromatography experiments were performed using a Varian 3800 GasChromatograph (GC) utilizing the thermal conductivity detector. Testadsorbents were packed into 10″ long, 0.25″ OD copper columns. Thecolumns were filled with approximately 3.5 grams of sample adsorbent.The adsorbents were activated at 250° C. for 10 hours under a flow of 30cc/minute helium carrier gas. Pulse injections were performed using 1 mLof argon, oxygen, methane, air, or mixtures thereof. This technique is auseful screening tool for determining separation characteristics and ismuch faster to perform than isotherm analysis. Single components wererun through the column to measure the elution time of each component gasfrom the column. These individual experiments are then used to assignthe order of gas elution in a mixture of two or more gases. In themixtures provided, a gas or gases that are excluded (not adsorbed) elutemore quickly than a gas or gas that is adsorbed. By determining whichgases are excluded and which are adsorbed, one can estimate a pore sizerange for the Sample tested. Three different gas mixtures were employed,including air (nitrogen/oxygen), air/methane, and argon/oxygen.

The size of a gas molecule is generally given by the kinetic diameter ofthat molecule (or atom) as calculated using a Lennard-Jones potentialfunction. The kinetic diameters of a variety of gas species have beencalculated (Hirschfelder, et al. Molecular Theory of Gases and Liquids.Corrected printing with notes added. John Wiley and Sons, End.: NewYork, 1964; Sircar, et al. Gas Separation by Zeolites. In Handbook ofZeolite Science and Technology, Auerbach, Carrado, Dutta Eds. MarcelDekker, Inc. New York 2003). The Lennard-Jones model treats a diatomicgas molecule as a soft sphere and interactions between that sphere areassumed to be against a fixed point or charge. For reference, theaccepted Lennard-Jones kinetic diameter for oxygen is 0.346 nm, forargon is 0.340 nm, for N₂ 0.364 nm, and for methane is 0.380 nm. Breck,D. W., Zeolite Molecular Sieves: Structure, Chemistry, and Use, JohnWiley & Sons, Inc., New York (1974).

In reality, a diatomic gas molecule is not perfectly spherical and anadsorbent structure is not rigid since the large number of atoms andbonds in the framework randomly vibrate; allowing the structure someflexibility. The combination of a non-spherical gas species interactingwith a flexible adsorbent provides a result that is not predicted by theLennard-Jones theory. In adsorptive fluid separations, the oxygenmolecule acts smaller than an argon atom by adsorbing into pores that donot retain any argon. These observations have also been made usingcarbon molecular sieves. See, for example, Jin, X, et al. Ind. Eng.Chem. Res. 45, 5775-5787 (2006), where the authors demonstrate theseparation of argon from oxygen by preferentially adsorbing the oxygenin a kinetic PSA cycle. The estimation of the effective pore size of theinventive titanium silicate molecular sieves may be guided by thecalculated Lennard-Jones kinetic diameters but, as the Lennard-Jonestheory fails to predict the experimental observations, the absolutevalues of the pore sizes for the adsorbents cannot be accuratelyassigned using those calculated diameters. By way of comparison, air(N₂/O₂) behaves in accordance with Lennard-Jones theory as O₂ is morequickly adsorbed on carbon molecular sieves (activated carbons havingpores having diameters close to the molecular diameter of N₂). Thisbehavior is exploited for PSA systems that are used to separate N₂ fromair by preferentially adsorbing O₂ during the cycle.

C. Results and Discussion

1. Crystal Structure

FIG. 1 a depicts the powder XRD pattern of Sample C1, a prior art ETS-4material which had not undergone any ion exchange (prepared according tothe method disclosed in the '939 patent). FIG. 1 f also depicts thepowder XRD pattern of Sample C2, a prior art material which had notundergone any ion exchange. FIGS. 1 b-1 e depict the powder XRD patternsobtained prior to any Ba ion exchange being performed on inventiveSamples 1, 3, 2, and 4 respectively. Finally, FIG. 1 g depicts thepattern of inventive Sample 5 which had not undergone any ion exchange.

The most intense reflection (I_(o)) in the XRD pattern for the ETS-4material in FIG. 1 a occurred at a 2-theta of 14.766° (corresponding toa d-spacing of 6.96 Å). Using the XRD pattern collected for ETS-4 on theRigaku instrument, the ratio of the intensities of the major reflectionscan be normalized to the reference peak at 14.766°. The crystalstructure for ETS-4 produces an XRD pattern where all peaks are smallerthan the I_(o) peak at 14.766° (or d-spacing of 6.96 Å).

Powder patterns for inventive Samples 1-4 were similarly collected andnormalized to the peak at 14.766°. Each of these compounds includes atleast one, and typically plural, XRD peaks that are larger than thereference peak used in ETS-4 to describe compounds within the '939patent. Two peaks in the Sample 1 and Sample 4 titanium silicatemolecular sieves are more intense than the benchmark reflection.

However, subsequent analysis of prior art and inventive molecular sievesshow that it is difficult to distinguish the two on the basis of XRDpatterns. For instance, FIG. 1 f shows the pattern of prior art material(namely Sample C2) and FIG. 1 g shows the pattern of inventive material(namely Sample 5). Both show relatively similar peak ratios relative tothe benchmark reflection. It is speculated that the apparent differencein peak ratios observed in Samples 1-4 may have been due to differencesin the preparation of the samples prior to analysis.

The crystal structure of the molecular sieves of the invention hassubstantially similar lattice spacings as zorite. But while XRD analysismay not readily distinguish these materials, clearly they differ incomposition and in gas separation characteristics.

2. Composition

As is evident from the composition data in Table 3, all comparativesamples prepared in accordance with the prior art either had fluorineanion content or had no halide anion content. On the other hand, all thesamples of the invention had significant halide content other thanfluorine (being either chlorine or iodine). Halide content asrepresented by the variable w was typically between about 0.01 and 1.The presence of measurable quantities of halide in the inventivemolecular sieves, both pre-and post-ion exchange, strongly indicatesthat the halide is a functional part of the framework.

Looking at the comparative Samples C2-C7, it appears that fluorine israpidly and essentially completely removed from these prior artmolecular sieves during ion exchange. However, inventive Samples 5-10retain halide anion content under similar ion exchange conditions. Thepresence of larger Cl anions in the inventive samples may impedediffusion into the framework of the sieves and hence may influence boththe effective pore size measured by GC analysis (below) and the rate atwhich the ion-exchange reactions take place.

Based on the observed results for Samples 11-14, temperature plays asignificant role in the extent of Ba exchange but not necessarily inanion exchange. However, ion exchange reactant concentration did notseem to play such a significant role. It appears that the amount ofanion and cation in the materials can be independently controlled bycontrolling the exchange conditions.

Also as can be seen from Table 3, inventive Samples 16, 18, 20, 25, and26 were all prepared from comparative material C2 by ion exchanging forvery long periods of time (8 hours and up) with BaCl₂. These samplesillustrate that Cl can be introduced into prior art materials withsufficient (greater than prior art) exchange conditions. Unlike priorart, Ba-exchanged materials, these Samples unexpectedly containedsignificant Cl content.

3. Gas Separation

For each Sample, those gases and/or gas mixtures for which inverse gaschromatograms were obtained are listed in Table 3. Also, Table 3indicates the smallest gas in the mixtures tested that was excluded byeach Sample adsorbent. Oxygen is “smaller” than argon with respect toadsorption in the pores of the Samples during this testing,notwithstanding the fact that argon has a kinetic diameter that issmaller than oxygen.

FIG. 2 a is a gas chromatogram of the elution of a methane-air mixturethrough comparative Sample C1 in the Examples illustrating separation ofmethane and air using the molecular sieve. FIGS. 2 b-2 d are gaschromatograms of the elution of a methane-air mixture through Samples 1,3 and 2 respectively in the Examples illustrating separation of themixture into three separate fluid streams enriched in methane, oxygenand nitrogen. FIG. 2 e is a gas chromatogram of the elution of airthrough Sample 4 in the Examples where the single peak shows noseparation of nitrogen, oxygen or argon.

FIGS. 2 k-2 o are gas chromatograms of the elution of a methane-airmixture illustrating the effect of ion exchange time on the inventivestarting material of Sample 5 (the exchanged series being Samples 6-10).These can be compared to FIGS. 2 f-2 j, which illustrate the effect ofsimilar ion exchange times on the comparative starting material ofSample C2 (the ion exchanged series being Samples C3-C7). FIGS. 2 u-2 yare gas chromatograms of the elution of an argon-oxygen mixtureillustrating the effect of ion exchange time on the inventive startingmaterial of Sample 5 (again, the exchanged series being Samples 6-10).These can be compared to FIGS. 2 p-2 t, which illustrate the effect ofsimilar ion exchange times on the comparative starting material ofSample C2 (again, the ion exchanged series being Samples C3-C7).

For example, FIGS. 2 k-2 o and 2 u-2 y for the inventive series Samples6-10 show that initially both argon and oxygen are excluded. But, withlonger ion exchange times, oxygen begins to penetrate the adsorbent,indicating that the pore size is increasing. On the other hand, FIGS. 2f-2 j and 2 p-2 t for the Comparative series C2-C7 show that initiallyonly methane is excluded and that there is no apparent change with ionexchange time. The preceding data suggests that pore size may becontrolled by anion content and that gas capacity (i.e. retention time)is controlled by Ba cation content. For instance, prior art Samples C2to C7 demonstrate that the retention time increases with increasing Bacontent but the pore size does not change otherwise as a function ofexchange. At equivalent barium levels, samples containing chlorine willhave smaller pores than samples which do not contain chlorine.

FIGS. 2 z-2 ac pertain to elution of a methane-air mixture throughinventive Samples 11-14. FIGS. 2 ad-2 ag pertain to elution of anargon-oxygen mixture through inventive Samples 11-14. These Figures showthe effect of BaCl₂ concentration and temperature during the ionexchange reaction. The higher temperature leads to a greater amount ofion exchange, which in turn results in increased pore size. BaCl₂concentration has less effect. These Figures show that only methane isexcluded in Samples 11 and 12, while Samples 13 and 14 exclude argon.

FIGS. 2 ah-2 ai pertain to elution of an argon-oxygen mixture throughinventive Samples 22-23 and illustrate the effect of pH during the ionexchange reaction. The comparable stoichiometry of these two materialsindicates that pH may not be significant for either anion or cationexchange at low exchange temperatures. At longer times or highertemperatures, the pH may have more of a directing influence on thematerial characteristics.

FIG. 3 a shows isotherm data for Sample 1 pre-ion exchange. FIG. 3 bcompares isotherm data for Sample C1 to that of Sample 1. The isothermdata shown in these Figures indicates that prepared adsorbents cancompletely exclude methane even up to very high partial pressures. Theprior art material, Sample C1, does not exclude methane as effectivelyas the inventive material, Sample 1. Further, the isotherm datacorroborates the conclusions drawn by the GC chromatograph technique.The GC technique may not be sensitive enough to discern minordifferences between samples. The isotherms are more sensitive and cansubstantiate differences between materials that the GC technique doesnot.)

The present application has been described with reference to examples ofpreferred embodiments. It will be apparent to those of ordinary skill inthe art that changes and modifications may be made without departingfrom this invention.

1. A crystalline titanium silicate molecular sieve having a formularepresenting mole ratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX wherein M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X is a halide anion other than fluorine, or a combination ofanions excluding fluorine, and w is greater than
 0. 2. The titaniumsilicate molecular sieve according to claim 1 wherein w is less than 1.3. The titanium silicate molecular sieve according to claim 1 wherein wis greater than about 0.01.
 4. The titanium silicate molecular sieveaccording to claim 1 wherein X is Cl.
 5. The titanium silicate molecularsieve according to claim 1 wherein z is from about 5 to about
 40. 6. Thetitanium silicate molecular sieve according to claim 1 wherein y is atleast 2 and up to about
 5. 7. The titanium silicate molecular sieveaccording to claim 1 wherein M₁ consists of metal cations.
 8. Thetitanium silicate molecular sieve according to claim 7 wherein M₁ isselected from IUPAC classification Groups 1-3 metals, Group 8-12 metals,alkaline earth metals, rare earth metals, and all combinations thereof.9. The titanium silicate molecular sieve according to claim 8 wherein M₁comprises barium.
 10. The titanium silicate molecular sieve according toclaim 9 wherein M₁ additionally comprises sodium and potassium.
 11. Thetitanium silicate molecular sieve according to claim 1 wherein themolecular sieve has a crystal structure having substantially similarlattice spacings as zorite.
 12. The crystalline titanium silicatemolecular sieve according to claim 11 wherein at least one peak of itsXRD pattern has an intensity greater than an intensity of a peak at ad-spacing of 6.96 Å.
 13. The titanium silicate molecular sieve accordingto claim 1 having a pore size that ranges from greater than about 2 Å toabout 5 Å.
 14. A process for preparing the titanium silicate molecularsieve according to claim 1, comprising: providing a source of silicon, asource of titanium, a source of alkalinity, a metal salt, and a halideanion source other than fluorine, to form a composition where the moleratio of SiO₂/Ti is greater than about 1, H₂O/SiO₂ is greater than about2 and M₁/SiO₂ is from about 0.1 to about 10; and processing thecomposition at a temperature and for a period of time effective toproduce the molecular sieve.
 15. The process according to claim 14further comprising performing ion exchange on the titanium silicatemolecular sieve to produce an ion-exchanged titanium silicate molecularsieve having a formula representing mole ratios of oxides ofnM₂O:TiO₂:y SiO₂:zH₂O:wX wherein M₂ is at least one metal cation and nis from about 1 to about
 2. 16. The process according to claim 15wherein barium is exchanged for cations M₁ in the titanium silicatemolecular sieve.
 17. The process according to claim 16 wherein M₁ in thetitanium silicate molecular sieve comprises sodium, potassium orcombinations thereof.
 18. The process according to claim 17 wherein M₂in the ion-exchanged titanium silicate molecular sieve comprises barium,sodium, and/or potassium.
 19. The process according to claim 15 wherethe source of silicon is silica, silica hydrosol, silica gel, silicicacid, alkoxides of silicon, alkali metal silicates, and mixturesthereof.
 20. The process according to claim 14 wherein the metal salt isthe halide anion source.
 21. The process according to claim 20 where themetal salt is a Group 1 metal halide.
 22. The process according to claim21 where the Group 1 metal halide is sodium or potassium chloride,iodide, or mixtures thereof.
 23. The process according to claim 22 wherethe Group 1 metal halide is potassium chloride, potassium iodide, ormixtures thereof.
 24. The process according to claim 14 where the sourceof alkalinity is an alkali metal hydroxide.
 25. The process according toclaim 24 where the alkali metal hydroxide is a Group 1 metal hydroxide.26. The process according to claim 25 where the alkali metal hydroxideis sodium hydroxide or potassium hydroxide.
 27. The process according toclaim 14 wherein the source of titanium is a titanium halide.
 28. Theprocess according to claim 27 wherein the source of titanium is TiCl₃.29. The process according to claim 14 where processing comprises heatingwithin a range of from about 100° C. to about 300° C.
 30. The processaccording to claim 29 comprising heating for a period of time rangingfrom about 8 hours to 40 days.
 31. The process according to claim 14further comprising processing while controlling pH values within therange of from about 10.45 to about 11.0±0.1.
 32. A process for adjustingthe pore size of the titanium silicate molecular sieve according toclaim 1 comprising performing ion exchange on the titanium silicatemolecular sieve to produce an ion-exchanged titanium silicate molecularsieve having a formula representing mole ratios of oxides ofnM₂O:TiO₂:ySiO₂:zH₂O:wX wherein M₂ is at least one metal cation.
 33. Theprocess according to claim 32 wherein w is greater than about 0.01. 34.The process according to claim 32 wherein X comprises Cl.
 35. Theprocess according to claim 32 wherein barium is exchanged for cations M₁in the titanium silicate molecular sieve.
 36. The process according toclaim 32 wherein M₁ in the titanium silicate molecular sieve comprisessodium, potassium or combinations thereof.
 37. The process according toclaim 36 wherein M₂ in the ion-exchanged titanium silicate molecularsieve comprises barium, sodium, and potassium.
 38. A crystallinetitanium silicate molecular sieve having a formula representing moleratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX wherein M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X consists of halide anions other than fluorine, and w isgreater than 0, and wherein the titanium silicate molecular sieve isproduced by the process according to claim
 14. 39. A composition,comprising: a crystalline titanium silicate molecular sieve having aformula representing mole ratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX wherein M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X is a halide anion other than fluorine, or a combination ofanions excluding fluorine, and w is greater than 0; and from greaterthan zero weight percent to less than one hundred percent of at leastone additional material.
 40. The composition according to claim 39wherein the at least one additional material is an inert material, anactive material, or combinations thereof.
 41. The composition accordingto claim 39 wherein the at least one additional material is a syntheticzeolite, a naturally occurring zeolite, a desiccant, a catalyst, a clay,silica, a metal oxide, or combinations thereof.
 42. The compositionaccording to claim 39 wherein the at least one additional material is azeolite.
 43. The composition according to claim 50 wherein the at leastone additional material is a catalyst.
 44. The composition according toclaim 41 wherein the clay is a montmorillonite or a kaolin clay.
 45. Thecomposition according to claim 41 where the clay is a sub-bentonites orkaolin commonly known as Dixie, McNamee, Georgia and Florida, or othersin which the main constituent is halloysite, kaolinite, dickite, nacriteor anauxite.
 46. The composition according to claim 39 wherein the atleast one additional material is a porous matrix material.
 47. Thecomposition according to claim 46 wherein the porous matrix material issilica-alumina, silica-magnesia, silica-zirconia, silica-thoria,silica-berylia, silica-titania, as well as ternary compositions, such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia.
 48. The composition according to claim 39comprising from greater than 1 percent to at least 90 percent titaniumsilicate molecular sieve by weight of the composition.
 49. Thecomposition according to claim 48 comprising from about 2 to about 50percent titanium silicate molecular sieve by weight of the composition.50. An adsorber for use in an adsorption separation process, comprisingan adsorbent comprising a titanium silicate molecular sieve having aformula representing mole ratios of oxides ofnM₁O:TiO₂:y SiO₂:zH₂O:wX where M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X is a halide anion other than fluorine, or a combination ofanions excluding fluorine, and w is greater than
 0. 51. An adsorptivefluid separation process, comprising: providing a titanium silicatemolecular sieve having a formula representing mole ratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX where M₁ is at least one metal cation, n is fromabout 1 to about 2, y is from about 1 to about 10, z is from 0 to about100, X is a halide anion other than fluorine, or a combination of anionsexcluding fluorine, and w is greater than 0; and contacting the titaniumsilicate molecular sieve with a feed fluid mixture comprising at least afirst component and a second component to produce at least one productfluid enriched in the first component relative to the second componentusing an adsorption process.
 52. The process according to claim 51comprising a pressure swing separation process.
 53. The processaccording to claim 52 comprising a rapid cycle pressure swing separationprocess.
 54. The process according to claim 51 where the feed fluidmixture comprises nitrogen and methane, and the product fluid isenriched in methane.
 55. An adsorptive fluid separation process,comprising: providing a titanium silicate molecular sieve having aformula representing mole ratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX where M₁ is at least one metal cation, n is fromabout 1 to about 2, y is from about 1 to about 10₁ z is from 0 to about100, X is a halide anion other than fluorine, or a combination of anionsexcluding fluorine, and w is greater than 0; and contacting the titaniumsilicate molecular sieve with a feed fluid mixture comprising methane toproduce at least one product fluid enriched in methane using anadsorption process.
 56. The process according to claim 55 comprising apressure swing separation process.
 57. The process according to claim 56comprising a rapid cycle pressure swing separation process.
 58. Acrystalline titanium silicate molecular sieve having a formularepresenting mole ratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX wherein M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X consists of halide anions other than fluorine, and w isgreater than 0, and wherein the titanium silicate molecular sieve isproduced by the process according to claim
 15. 59. A crystallinetitanium silicate molecular sieve having a formula representing moleratios of oxides ofnM₁O:TiO₂:ySiO₂:zH₂O:wX wherein M₁ is at least one metal cation, n isfrom about 1 to about 2, y is from about 1 to about 10, z is from 0 toabout 100, X consists of halide anions other than fluorine, and w isgreater than 0, and wherein the titanium silicate molecular sieve isproduced by the process according to claim 32.